harnickell



2 Sheets -Sheet 2.

A. HARNIOKELL. v Spelter Furnace. No. 23 ,221. Patented Jah. 4,1881.

wihfesses, V v 353mm m (a ATENT Erica.

ALBERT HARNIOKELL, OF BROOKLYN, NEW YORK, ASSIGNOB TO GEORGE A. POPE AND GEORGE B.-GOI]E, OF BALTIMORE, MARYLAND.

'SPELTER-FURNACE.

SPECIFICATION formingpart of Letters Patent No. 236,221, dated January 4, 1881.

' Application filed March 14, 1879.

To all whom it may concern Be it known that I, ALBERT HARNICKELL,

of the city of Brooklyn, Kings county, State of New York, have invented certain new and useful Improvements in Spelter-Fnrnaces; and I hereby declare the same to be fully, clearly, and exactly described as follows, reference being had to the accompanying draw ings, in which- Figure 1 is a horizontal sectional view of the furnace, and Fig. 2 a vertical sectional view of the same. The left half of'Fig. 1 is a section on line 1 2, theright half on line 34, of Fig. 2, which latter is a section on line 5 6, Fig. 1. Fig. 3 is a vertical longitudinal sectional view of one of the retort chambers or furnaces; Fig. 4, a similar view, showing the means for heating the retorts simultaneously from without and within. Figs..5 and 6 are end eleva-. tions of the retort-furnaces Figs. 7, 8, 9, 10, detail views, as hereinafter explained.

My invention has for its object to attain a result on a commercial scale heretofore only reached, and even then but imperfectly, in the laboratory-namely, the production of an article of zinc free from all impurities.

The zinc reduced from zinc-white made from pure ores has heretofore been regarded as the nearest approximation to pure metal; butthis source is inadequate to supply the increasing demand for pure zinc to be usedin the manu-v facture of high-grade brass for spinning and cartridge-shells. Besides, the article leaves much to be desired in point of quality, and is very expensive.

My invention consists in certain novel forms of apparatus designed with special reference to the purification of zinc, but also, by'reason of certain peculiarities of construction, equally adapted for other purposes, as the metallur box, which is supplied with air from the ashpit in the usual way, and from which lead the lire-canals J J over bridge-walls H H. The fire passes through combustion-chambers K K, located in the retort-furnaces, from which chambers it passes through openings cl d, over the retorts P P, and thence, through similar openings on the opposite side of the retorts, into passages L L, which communicate, by means of smoke-fines M M, with the chimney E.

Q Q are suitable dampers covering the ends of the'channels L L.

Each retort-chamber N is divided lon gitudinally by a hollow pillar-wall, X, upon which rests the retort P, the openings 0 0 0 0 being connected and leading through openings O O into the fire-box above and below the grate, as shown in dotted lines, Fig. 2. The flues'o 0, from the lateral retort-chambers, meet the vertical flue between the stack E and the gratechamber, and contiguous to the latter, and from this vertical flue openings O lead, as clearly shown in Fig. 1, opening into the firebox, one opening being above and the otherbelow the grate. The flues 0 receive air through openings 0 in the outer walls. (See Fig. 3.) By these means a hot blast, as it were, may be supplied to the fire-box, or let into the furnaces through valves 70, worked by dampers V, the air being heated in its passage through the channels 0 0. This hot blast may be used or not, as desired. v Thevalves cover openings in the masonry partition between the chambers K and the flues 0, and are slid back and forth by means of the dampers V, wholly or partly uncovering the openings. The retorts are provided at one end with a charginglip, A, and at the other with an inclined condensing-pipe, R, which leads to the receivers B, which latter are preferably arranged to be set in the masonry over the smoke-fines M.

Now, as to the construction of the various parts in detail, it may be said the retorts P are made of goo ay, and'are provided with charging-nozzles A, f any desired shape,

at one end, and with condensingpipes B at the other. These latter are slightly inclined, as shown in Fig. 3, and enter' the receivers B. These latter are of suitable external shape and size, and are provided with apartition, S, that is perforated at a point just under the end of the pipe R. Tap-holes are formed in the receiver near the bottom, and also just above the partition S, for letting out the contents when desired. A water-jacket, a, is applied to the pipe It when it is necessary to lower its temperature.

T is a pipe inserted in the side of the receiver opposite the pipe It, with which it accurately registers, or into which it enters when pushed inward. Its construction is shown in detail in Fig. 7, wheref represents a semicircular partition halt closing the pipe.

0 is a rod carrying a semicircular scraper, f on its end, adapted to serve, in connection with the partition f, to completely close the pipe T. The end plate of the pipe is provided with a glass or mica window, t, through which the color in the retort may be observed. These details of construction are not shown in Fig. 3, a simple discharge-nozzle being shown as inserted in the pipe T.

1), Figs. 8 and 9, is the casting-mold. It is made, by preference, of zinc, and is provided with a cup, I, to receive the metal as it is poured, and a neck, 0, leading to the main mold D. On either side of the neck are lugs g, serving as bearings for the skimmerj, Fig. 10. Pins 1) b on either side of the mold D support it in the water-bath U. The skimmer is provided with lugs j j, that rest between the lugs g, the part j resting in the neck a, and serving to skim the metal as it flows under it and retain any dross or oxide.

In Fig. 4 is shown the device used for tempering a new retort. pipes O 0 being made to lead, respectively, into the retort from the fireflue J, and from it into the smoke-flue M. By these means the retort is heated simultaneonsly from without and from within, greatly lessening the danger of cracking it.

I proceed to the preparation of the retort for the metallurgical operations as follows: Upon obtaining a bright heat in the retort, I proceed to the manipulation of closing the pores and fire-cracks inside and rendering the retort perfectly metal-proof and capable of holding, in liquid or gaseous state, any or all metals, without leakage or penetration into the substance of the retort. To effect this I make use of the phenomenon occurring in making illuminating-gas when a retort is worked unskillt'ully or for too long a timeviz., that of earbonizing. In that process coalgas is generated, and it is a desideratum to avoid as far as possible its decomposition. I, on the contrary, aim at and obtain a regular and sufficiently thick and smooth deposit of graphitic carbon on the interior of the retort by conducting into it ahydrocarbon gas obtained from coal-tar, tallow, rosin, or other equivalent substance, and maintaining the gas under pressure in the retorts while subjected to a decomposing heat. Small safety-jets l llead from the retorts, for the escape of the highly hydrogenous products of decomposition of the gas, which are ignited, as shown. In about forty-eight hours the process is complete. The condenser and receiver are next connected with the retort, and the latter is ready for charging.

In case an alloy or mixture of zinc and iron is to be treated, a thick layer of ordinary carbon is introduced on the bottom of the retort. In the case of alloys of zinc which fuse with difficulty, such as the zinc-silver scum from Parkes method of extraction, or the bottoms of galvanizers baths, the same are introduced into the retort by means of a double gate-110pper or similar air-excluding device.

Alloys that are readily fusible are first treated in kettles, the object being a preliminary partial separation of lead, tin, iron, arsenic, 850., by the processes of physicking and liqnation. I, however, add any reagents used, such as sulphur, below the surface of the bath, filling them into tubes, which are plunged to the bottom of the kettles, insuring a more per feet distribution of the reagent than is possible by the usual process of stirring, while avoiding certain disadvantages attending the latter method.

The next manipulation takes place in the retort-furnaee--viz., that of charging metal. In the matter of composing the charge, in view of traces of impurities left in from the previous operations, the operator avails himself of well-known principles of metallurgy to vary the admixture of fluxes or reagents, according to the nature of the metal under treatment. As the heat in the retortis sufficient to render any alloy of zinc fluid, the operation of charging is repeated at intervals, but not beyond filling the retort half full, nor so quickly as to cool the inside of it seriously. The heat in the chamber is kept at the distilling-point of zinc. In the retort it is, of course, lower during the act of filling in.

Simultaneously with the operation of charging, another manipulation takes place at the rear end of the retort-viz., the long pipe T is pushed through the receiver B into the condensing-pipe It, thus closing the receiver and leaving as the only outlet from the retort the pipe T. This lattermay be kept shut by means of a simple outlet-valve, s, or left open to allow of the escape of non-metallic gases, if any are expected to form; but the air must be kept out of it; hence it is better that the valve should close automatically. The result of the operation at this point is the volatilization successively, according to their distillingpoints, of all metals in the retort which are volatile below the distilling-pointof zinc, such as cadmium, antimony, arsenic, mercury, 85c. They condense in the pipe T, which is cool, and are scraped toward its opening by manipulatin g the scraper f, as explained above. The receiver is thus kept closed until suflicient condensation of zinc in the pipe B gives evidence of the operation with the fugitive metals being completed. Where it is worth while to save any of these metals, as cadmium,

ICC

I the'samefis' secured separatelybykeeping the pipe well" cleaned of substances condensing prevlousto its yaporization.

Where poisons, like arsenic, antimony, or

I mercury, are expected, or their presence in the retort is :suspected in any appreciable quanreach the full distilling-point of zinc. Zinc,

however, will distill overwith the mercury in small quantity and lodge in the receiver, in which the heat will be sufficient to continue drivin'g m'ercu'ry into the cool pipe T. The zinc in the receiver is disposed of for common purposes, and the contents of the retort are tapped for redistillatiom'or made into paints, since traces of mercury may still remain; the quicksilver will be found pretty. pure.

Referring, again, to'the regular process at this stage-via, upon the appearance of solid orliquid zinc in quantity ingthe extension-pipe T-the next manipulation takes place, viz: the pipe T is drawn out of the condensing-pipe R, soas to leave its small endflush with the inner side of the receiver. Now" the zinc in the retort distills over, condensing in the pipe R, which is heated by the great latent heat set free by the zinc in passing from a gaseous to a liquid state, at first sufficiently and afterward more than sufficientlyto preventsolidification. The metal runs out of this pipe through the orifice in the false bottom to the warmed bottom of the receiver B, where it accumulates. irregularities are corrected by the opportunity given by the cool false-bottom part of the receiver and the cooler exten sion-pipe T being open to the lodgment of zinc dust, oxide, and impurities. When the condensing-pipe 1% becomes red hot only zinc goes over. At this time the water-jackets a are applied around it to reduce its temperature and give it ample capacity to condense all zinc-gas ascending, so that the same shall not be condensed in the receiver or extension-pipe, nor run in a red-hot state into the lower receptacle.

At regular intervals, and before charging again, the manipulation of tapping the receiver takes place. The lower tap-hole is opened and the lower receiver emptied. The resultant zinc is chemically pure. The contents are allowed to cool without chilling them, until the skin, with adhering clay or dirt, can be taken off in one dip.

The next manipulation is that of casting. This is done in the water-mold D, described above, (which has previously been polished, and for castings for rolling is set slightly out of its level, so as to yield the usual tapering plate.

The object of the precautions for coolin g the zinc taken alreadyin the condenser, the keeping it at moderate heat in the receiver, cooling it before casting, combing it with the automatic comb j, and chilling it at the period of its solidification, is not that of rendering each plate or eastin g suitable for rolling, in respect to which use the chilling would be generally considered fatal with ordinary spelter, but is twofold, tending to one result. The low temperature is to prevent burning ofthe zinc and its alloying or mixing with any zinc or other metal dust or zinc-white which, through some irregularity, might come in contact with it, thereby preserving chemical purity, the combination of which quality, with calm fusion and solidity of casting, produces for the product of this art the highest known specific gravity of unwrought zinc, equal to that of the common rolled zinc.

The zinc produced and cast in the manner described is eminently adapted for any and all uses. such as for the chemical laboratory,for

medicinal uses, for colors, for rolling, drawpretty well filled with metal, it is again charged with about the same quantity of raw material as that of metal tapped fro m the receiver. The manipulations of the extension-pipe an d Waterjacket are repeated, the same as when commencing, only now the period of closing the receiver, as dictated by the phenomenon of "zinc appearing, is naturally shorter. This process may go on indefinitely in treating material having only traces of other metals besides zinc, as in case with that previously treated in the kettle-furnace. For that containing much iron, copper, tin, or lead not removed before filling into the retort, and for that material which contains precious metals, the process is varied.

When zinc silver lead alloy has been charged, when the retort is half full or less, and zinc has ceased to distill over, the condenser is emptied and the heat increased, so as to remove the last traces of zinc. When this is finished the front plate of the retort is tapped and the resulting lead-silver alloy cast into pigs for cupelling, while the zinc, oxide, and dust are removed from the retort and condenser, and accumulated for a final reduction with fine coal in the same retort, the resultant zinc from which operations possibly containing gold and silver, must be used again in the zincing process at the silver-works, while the product of the simple distillation is free of other metals. At the end of an engagement compared with the processes of distilling off the zinc from this alloy now practiced, my invention, as bearin g thereon, possesses the following advantages, viz: Facility for operating on a large scale in one furnace, with attending economy of plant, of retorts, of fuel, and of laher. The liability of loss from particles of noble metal being buried in the body of the retort is lessened and the durability of the retorts increased.

WVhen copper, lead, tin, &c., are residue in quantityin a retort, they are simply tapped out in front and cast.

When iron alone is expected to bethe residue and would form a sow, then, when intending to run the retort empty, the heat is increased to a real white heat; next carbon and fluxes are introduced to melt the iron in 1000, which done, it is promptly tapped out; but where iron, tin, lead retain zinc in a combination difficult to deal with except by distillation, then upon' zinc ceasing to flow the extension-pipe is pushed into the condenser, the water-jacket is put on, and the heat increased to a. point which may distill lead, &e. The condensed product, all in the pipe, is not cast, but returned to the kettle-furnace. The residue in the retort is scraped out or dealt with by way of fusion.

I am aware that carbon-lined crucibles are old, and that it is also old to use the carbon from coal-gas retorts in the construction of crucibles. Such I do not claim, nor do I claim the mold hereinbefore described. I have been minute in describing it and its functions in connection with my process and apparatus, because I believe it to be the best form of mold to be used in connection therewith.

What I claim is- 1. In combination with the fire box and stack, the tines J M K L, retort chambers and furnaces N, as set forth.

2. In combination with the common fire-box G, the retort-furnace wings located at either side of the same and provided with channels J K L and ducts M, leading to the common stack E, the channels L being provided with dampers Q, as set forth.

3. The retort-furnaces N, having openings 0 O communicating with the fire-box below or above the grate, or both, as described.

In combination with the retort P and pipe It, the receiver B, having perforated false bottom S, as set forth.

5. In an apparatus for separating zinc from other metals, the receiver B, having registering condensing-pipes R T, as set forth.

6. In combination with the retort P, the receiver B, having the inclined registeringpipes B T, for the discharge of condensed products and for the inspection of the colorin the retort, as described.

7. In combination with the receiver B, the pipe T, having semicircular partition f and scraper f, substantially as described.

8. In combination with the retort-furnace N and flues J KL M, the pipes 0, connecting the fines M J with the interior of the retorts, as described.

9. The method herein described of rendering metallurgical retorts metal-proof or impervious to the molten metals, consisting in decomposingwithin the retorts a hydrocarbon gas, whereby the walls of the retorts become coated and impregnated with graphitic carbon, as set forth.

10. In an apparatus for the separation of zinc from other metals by distillation, a retort having its interior surface coated with graphitic carbon deposited from a hydrocarbon decomposed within the retort, as set forth.

ALBERT HARNICKELL.

Witnesses G110. A. POPE,

It. D. WILLIAMS. 

